Abstract. The polar stratospheric ozone loss during the Arctic
winters 2004/2005–2009/2010 is investigated by using
high resolution simulations from the chemical
transport model Mimosa-Chim and observations from
Aura Microwave Limb Sounder (MLS), by applying the
passive tracer technique. The winter 2004/2005 shows
the coldest temperatures, highest area of polar
stratospheric clouds and strongest chlorine activation
in 2004/2005–2009/2010. The ozone loss diagnosed
from both simulations and measurements inside the
polar vortex at 475 K ranges from 0.7 ppmv in the
warm winter 2005/2006 to 1.5–1.7 ppmv in the cold
winter 2004/2005. Halogenated (chlorine and bromine)
catalytic cycles contribute to 75–90% of the ozone
loss at this level. At 675 K the lowest loss of
0.3–0.5 ppmv is computed in 2008/2009, and
the highest loss of 1.3 ppmv is estimated in
2006/2007 by the model and in 2004/2005 by MLS. Most of
the ozone loss (60–75%) at this level results from
nitrogen catalytic cycles rather than halogen cycles.
At both 475 and 675 K levels the simulated ozone and ozone loss
evolution inside the vortex is in reasonably
good agreement with the MLS observations. The ozone partial
column loss in 350–850 K deduced from the model
calculations at the MLS sampling locations inside
the polar vortex ranges between 43 DU in 2005/2006 and 109 DU
in 2004/2005, while those derived from the MLS observations range
between 26 DU and 115 DU for the same winters.
The partial column ozone depletion derived in that vertical
range is larger than that estimated in 350–550 K
by 19±7 DU on average, mainly due to NOx chemistry.
The column ozone loss estimates from both Mimosa-Chim and MLS
in 350–850 K are generally in good agreement with
those derived from ground-based ultraviolet-visible
spectrometer total ozone observations for the respective
winters, except in 2010.